Study on growth and utilization of alfalfa grown in Cdrich substrate

The improvement of coal mining subsidence land by finding the proper substrates with rich nutrition and suitable soil properties for crop has become the research focus at the case of soil become the scarce resource. Three substrate formulas, including fly ash + sewage sludge (substrate 1), fly ash + lees (substrate 2) and fly ash + furfural residue (substrate 3), were used to study the effect on alfalfa cultivation. The results showed that the alfalfa yield was low and the dry matter based Cd content in alfalfa was over the health standard in the first year due to the high contents of salt and Cd, however, it could be used as fresh fodder for livestock or green manure. Due to the plant absorption and leaching in the first year of, the content of salt in the substrates declined to the normal level and the alfalfa yield achieved the normal level, the Cd content in substrates reduced to 4 to 6 times of environmental quality standards, and the dry matter based Cd content in alfalfa reached the health standard.